Information-Oriented versus Service-Oriented Adapters

Another clear trend in the world of adapters is the movement from simple information movement to support for service-level application connectivity. As you may guess, each approach requires very different types of adapter technology.

When dealing with simple information, the information-oriented adapter merely leverages whatever interface is available to extract information from the source system, and moves that information into the integration server (see Figure 10.5). For example, customer-address information coming from SAP may be transformed to account for differences in application semantics and then published to a target system (or systems), say, PeopleSoft, using the same type of information-oriented adapter.

Figure 10.5. Information-oriented adapters deal only with simple information.

Service-oriented adapters are a bit more complex. Instead of dealing with the extraction and publication of simple information to source or target systems, service-oriented adapters have to abstract services or application behavior, as well. In other words, they need to expose application functions in a way that they may be abstracted into a composite application as a local function that actually exists on a remote system. Remember, even though the function appears local to the composite application, the application processing occurs in the remote system that is connected through a service-oriented adapter (see Figure 10.6).

Figure 10.6. Service-oriented adapters are able to abstract remote application services to composite applications that can make use of them.

In essence, service-oriented adapters take remote function calls within remote systems for other applications, and do so without the applications having to understand anything about each other. Of course, service-oriented adapters have to be linked through some type of integration server or application server to facilitate the extension into the composite applications, and to account for the differences in the applications.

Service-oriented adapters are a result of the interest in SOAI and the use of standards such as Web services, and perhaps some lingering use of more traditional distributed objects. However, creating service-oriented adapters, in practice, is a bit of challenge considering that the adapter has to interact with internal application functions, rather than just application information.